51ef917303
As per analysis, it appears that the 'drop slot' message from the previous test and 'create slot' message of the new test are either missed or not yet delivered to the stats collector due to which we will still see the stats from the old slot. This can happen rarely which could be the reason that we are seeing some failures in the buildfarm randomly. To avoid that we are using a different slot name for the tests in test_decoding/sql/stats.sql. Reported-by: Tom Lane based on buildfarm reports Author: Sawada Masahiko Reviewed-by: Amit Kapila, Vignesh C Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
98 lines
3.9 KiB
PL/PgSQL
98 lines
3.9 KiB
PL/PgSQL
-- predictability
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SET synchronous_commit = on;
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SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot_stats', 'test_decoding');
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CREATE TABLE stats_test(data text);
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-- function to wait for counters to advance
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CREATE FUNCTION wait_for_decode_stats(check_reset bool, check_spill_txns bool) RETURNS void AS $$
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DECLARE
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start_time timestamptz := clock_timestamp();
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updated bool;
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BEGIN
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-- we don't want to wait forever; loop will exit after 30 seconds
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FOR i IN 1 .. 300 LOOP
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IF check_spill_txns THEN
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-- check to see if all updates have been reset/updated
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SELECT CASE WHEN check_reset THEN (spill_txns = 0)
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ELSE (spill_txns > 0)
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END
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INTO updated
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FROM pg_stat_replication_slots WHERE slot_name='regression_slot_stats';
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ELSE
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-- check to see if all updates have been reset/updated
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SELECT CASE WHEN check_reset THEN (total_txns = 0)
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ELSE (total_txns > 0)
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END
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INTO updated
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FROM pg_stat_replication_slots WHERE slot_name='regression_slot_stats';
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END IF;
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exit WHEN updated;
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-- wait a little
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perform pg_sleep_for('100 milliseconds');
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-- reset stats snapshot so we can test again
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perform pg_stat_clear_snapshot();
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END LOOP;
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-- report time waited in postmaster log (where it won't change test output)
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RAISE LOG 'wait_for_decode_stats delayed % seconds',
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extract(epoch from clock_timestamp() - start_time);
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END
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$$ LANGUAGE plpgsql;
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-- non-spilled xact
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SET logical_decoding_work_mem to '64MB';
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INSERT INTO stats_test values(1);
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SELECT count(*) FROM pg_logical_slot_get_changes('regression_slot_stats', NULL, NULL, 'skip-empty-xacts', '1');
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SELECT wait_for_decode_stats(false, false);
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SELECT slot_name, spill_txns = 0 AS spill_txns, spill_count = 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
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RESET logical_decoding_work_mem;
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-- reset the slot stats, and wait for stats collector's total txn to reset
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SELECT pg_stat_reset_replication_slot('regression_slot_stats');
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SELECT wait_for_decode_stats(true, false);
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SELECT slot_name, spill_txns, spill_count, total_txns, total_bytes FROM pg_stat_replication_slots;
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-- spilling the xact
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BEGIN;
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INSERT INTO stats_test SELECT 'serialize-topbig--1:'||g.i FROM generate_series(1, 5000) g(i);
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COMMIT;
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SELECT count(*) FROM pg_logical_slot_peek_changes('regression_slot_stats', NULL, NULL, 'skip-empty-xacts', '1');
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-- Check stats, wait for the stats collector to update. We can't test the
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-- exact stats count as that can vary if any background transaction (say by
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-- autovacuum) happens in parallel to the main transaction.
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SELECT wait_for_decode_stats(false, true);
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SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
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-- reset the slot stats, and wait for stats collector to reset
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SELECT pg_stat_reset_replication_slot('regression_slot_stats');
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SELECT wait_for_decode_stats(true, true);
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SELECT slot_name, spill_txns, spill_count, total_txns, total_bytes FROM pg_stat_replication_slots;
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-- decode and check stats again.
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SELECT count(*) FROM pg_logical_slot_peek_changes('regression_slot_stats', NULL, NULL, 'skip-empty-xacts', '1');
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SELECT wait_for_decode_stats(false, true);
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SELECT slot_name, spill_txns > 0 AS spill_txns, spill_count > 0 AS spill_count, total_txns > 0 AS total_txns, total_bytes > 0 AS total_bytes FROM pg_stat_replication_slots;
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-- Ensure stats can be repeatedly accessed using the same stats snapshot. See
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-- https://postgr.es/m/20210317230447.c7uc4g3vbs4wi32i%40alap3.anarazel.de
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BEGIN;
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SELECT slot_name FROM pg_stat_replication_slots;
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SELECT slot_name FROM pg_stat_replication_slots;
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COMMIT;
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DROP FUNCTION wait_for_decode_stats(bool, bool);
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DROP TABLE stats_test;
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SELECT pg_drop_replication_slot('regression_slot_stats');
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